Ad hoc networks are self-forming networks which can operate in the absence of any fixed infrastructure, and in some cases the ad hoc network is formed entirely of mobile nodes. An ad hoc network typically includes a number of geographically-distributed, potentially mobile units, sometimes referred to as “nodes,” which are wirelessly connected to each other by one or more links (e.g., radio frequency communication channels). The nodes can communicate with each other over a wireless media without the support of an infrastructure-based or wired network.
A wireless mesh network is a collection of wireless nodes or devices organized in a decentralized manner to provide range extension by allowing nodes to be reached across multiple hops. In a multi-hop network, communication packets sent by a source node can be relayed through one or more intermediary nodes before reaching a destination node. A large network can be realized using intelligent access points (IAP) which provide wireless nodes with access to a wired backhaul.
A mesh network therefore typically comprises one or more IAPs (Intelligent Access Points), and a number of APs (Access Points), which provide data service to STAs (subscriber stations). An AP can connect to IAP directly or through multi-hop route. Different mesh networks can operate in different channels and such channel selections are dynamically changeable. Hence, when a device travels at high speed (e.g. vehicular speed) or in a dense network area, it may need frequent handoff (i.e. transition from one mesh network to another). During the handoff, a device may scan a number of channels before determining a suitable channel and IAP to associate with. The scanning process can take as long as several seconds which can cause serious service or losing connectivity. One way to reduce the scan delay is to operate the access point to perform periodic scanning so that the scan results can be provided to a mobile device to assist in the handoff.
Accordingly, there is a need for a method and apparatus for enabling periodic scanning in wireless communication networks.
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The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.